


Kill them with Kindness

by Askellie (NadaNine)



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Bondage, Captivity, Emotional Manipulation, M/M, Medical Examination, Mind Control, Non-Consensual, Post-Undertale Pacifist Route, Soul Sex
Language: English
Status: Completed
Published: 2017-04-03
Updated: 2017-04-03
Packaged: 2018-10-14 06:55:24
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 3,354
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10531233
Author URL: https://archiveofourown.org/users/NadaNine/pseuds/Askellie
Summary: Frisk frees the monsters of Underfell and leads them to the surface where humans are waiting to meet them, not with LOVE, but with love.Sans always expected the worst, but even he never imagined how far humans would take their oppressive kindness and mercy to try and 'help' monsters recover from their world of kill or be killed.





	

**Author's Note:**

  * For [Germindis](https://archiveofourown.org/users/Germindis/gifts).



Sans rose from unconsciousness with his eye already blazing, the magic fire searing his eye-socket and dyeing the world in violent shades of red. He’d sworn that his eyes had been closed for only moment – a hard won reprieve in his battle against the human – but even as his vision cleared enough for him to take in his surroundings properly he knew he must have fallen asleep. He was no longer in the Judgment Hall. In fact, he had no idea where he was, but the fact that he was still alive and whole, lying in a soft bed with clean sheets told him that he’d failed. The merciful human had gotten past him, and worse, had let him live despite how hard Sans had tried to compel them to kill him.

If only they had gained some LOVE he was they would have understood that monsters should never be allowed to go free. His kind was too vicious and broken to be trusted with the world above. There would be more war, more death, and in the face of the vastly more numerous human population, monsters would undoubtedly lose again. The existence of one merciful human wasn’t an indication that the rest would be so generous. Monsters would rather die than face imprisonment underground again, and surely humans would oblige them this time.

Worst of all, Sans would still be alive to see it happen.

Cursing furiously under his breath he struggled to sit up only to fail, and he belatedly realised an important detail he’d overlooked in his initial assessment of the room; the restraints holding him to the bed.

“What the fuck?” he muttered, twisting his limbs, trying to pull free, but even though the restraints were thickly padded to avoid causing him any discomfort, they held him firmly prone on the mattress, arms pinned at his sides, legs slightly spread. His initial confused morphed quickly into dread as he struggled. He’d given his all, fighting the kid in the Judgment Hall. His body felt brittle, even weaker than usual, and aside from a brief spark in his eye-socket that made his skull twinge painfully, he couldn’t call on his magic at all. Sweat plastered his bones as he lay gasping for breath, his efforts quickly exhausting him. His mind scrambled desperately for options until a mechanical whirring jolted him from his thoughts. He sat up as much as he could, eye-lights constricted to tiny pricks of light as the door slid open and revealed a human.

An unfamiliar, adult human – tall and imposing, dressed in a long white lab coat that held several ominous looking implements in its pockets.

Before Sans could reflect on exactly how fucked he was, the human blinked and beamed at him, flat white teeth bared in an absurdly friendly smile. “Oh! You’re finally awake. You were beginning to worry us, you know.”

“Uh…” Sans gaped unintelligently, his mind blanking unhelpfully instead of providing him with an appropriately snappy retort.

The human drew near, and Sans flinched back, painfully aware of his helplessness, but the human merely drew up the chair that had been resting against the wall and sat down beside him, pulling out a clipboard. “How are you feeling?”

“Wha-…what the hell, who are you? Where the fuck is this?” Sans snarled, trying to mask his uncertainty with anger. Disappointingly, the human didn’t even bat an eye at his tone.

“Ah, my apologies. I’m sure you’re very confused. First of all, on behalf of humanity, welcome to the surface.” The human offered him another bright, even-toothed smile which Sans somehow found more unsettling than the fanged maws of Snowdin’s Canine Unit. “This is the monster conservation and protection center, where we are working towards the preservation and reintroduction of your species to the surface world.”

It was a combination of words that somehow made absolutely no sense. Sans stared, a hundred questions clamoring for precedence in his mind, but before he could voice a single one the door whirred a second time, admitting another human.

“Sorry, Doctor, I didn’t mean to be…oh! He’s awake!” The new human was also male, his features smoother (younger?) than the first. His coat seemed crumpled with haste, his name-badge knocked askew. Sans wanted to scoff at him, conveniently ignoring all the times he’d looked just as harried when he’d been an intern himself.

“And this is my assistant,” the Doctor continued with a fondly exasperated smile, gesturing for his partner to approach. “Who will be assisting by providing you with your treatments.”

Sans’s sockets narrowed warily. “Treatments for what?”

“For your LOVE, of course,” the Doctor said, his expression an odd mix of sternness and sympathy. He gave Sans a searching look. “You are aware that your LOVE is inordinately high for one of your kind.”

Sans bristled, glaring. Luckily these days, other monsters didn’t bother to check his stats. Boss treated him like garbage publicly and frequently, leading most to assume Sans’s LV was pitifully low. None of them recognised him from his days as Asgore’s Judge…hell, not that anyone would. The only people who saw Sans’s face during those days didn’t live to talk about it. Unfortunately, the promised numbness and callousness that came with acquiring LV had never affected him. The higher his level had climbed, the lower his stats had dropped until he’d been forced to quit on the very verge of falling down.

“What about it?” Sans grunted, trying and failing to stare the human in the eye. He wasn’t ashamed, he told himself. He was just…tired. Constantly exhausted from the weight of all those sins crawling on his back.

The Doctor shook his head sadly. “Monsters are meant to be made of love, not LOVE. I’m afraid all that time underground has had a devastating effect on the behavior of monsters. Forced you to unnatural acts of violence and hate…but don’t worry. Humans will find a way to cure you.”

The Doctor spoke with such conviction and enthusiasm – so much like Frisk and their sincere desire for mercy…Sans was almost taken in by it.

Almost.

“That’s…uh. That’s great,” he said, his voice flat enough not to give away his disgust. Humans thought they could fix monsters. What a joke. “How about you untie me first and we can talk about it, huh?”

“I’m afraid that’s impossible,” the Doctor told him pleasantly, moving to stand. On the other side of the bed, his Assistant had moved in, his sleeves rolled up and his hands freshly gloved in blue latex. Sans was boxed in on both sides, and still held flat to the mattress. The position was sending all manner of alarms through Sans’s skull. “Given your LOVE…well, I’m afraid the restrains are for our own safety. Besides, we wouldn’t want you to accidentally harm yourself during the procedure.”

“Why would I-?” Sans started, and then tapered off as the Doctor drew back the blanket over Sans’s body. He hadn’t given too much thought to it before, but underneath the sheet he’d been completely stripped of his clothing. His body looked especially small without the bulky layers he used to give an illusion of mass to his delicate frame. The instinctive flush of realising his nakedness was matched by an equal jolt of fear as the Doctor lay his large hands on Sans’s scarred rib cage. “What the fuck are you doing!? Get off’a me! Don’t fucking touch me!”

“There’s no need for alarm,” the Doctor said even though there was absolutely every fucking reason for alarm as far as Sans was concerned. He bucked against the hold, but the placement of the Doctor’s hands was seemingly intended to hold him in place so the Assistant could hover his own hands over Sans’s sternum. The Assistant’s face was a mask of concentration. Sans felt a faint tug on his soul.

Panic set in violently. Sans heaved, snarling and spitting, trying to contort enough to sink his fangs into anything he could reach. His phalanges scrabbled at the mattress, but unlike Boss, Sans didn’t bother to keep his claws sharpened these days. They didn’t even manage to tear the cloth let alone find any purchase in the thick restraints.

“Easy, easy,” the Doctor soothed as if Sans was some sort of wild animal to be subdued. His struggles lessened, but only because the tugging on his soul was starting to become an agonising squeeze, feeling unsettlingly like the early days when he’d first been teaching his brother to use blue magic and Papyrus had put his usual fierce energy into his first attempt. Sans’s soul had felt crushed and cruelly yanked into the open. This felt much the same, made worse by Sans’s attempt to resist it.

Finally, with a horrific twist that made Sans yelp in pain, his soul was forced free of his chest and into the Assistant’s hands. Immediately he closed his fingers around it, caging it between his palms, and Sans felt a foreign rush of satisfaction flooding through his core. The gloves dimmed the raw exchange of emotion that would normally take place, but it was still unwelcome and intrusive.

“There you go. That wasn’t so bad,” the Doctor said, pulling out a cloth and absently dabbing at the sweat pouring down Sans’s skull. Sans wheezed, bones trembling with a soft clatter, unable to look away from where his soul was held captive. The Assistant held him carefully, his own soul resonating a soft pulse of calming green ambience.

A green soul. A kind soul. Of all possibilities, that was probably the least unsettling, though Sans was in no way placated by the Doctor’s reassurances. Unfortunately, with his soul exposed and vulnerable, he found himself unwillingly susceptible to the Assistant’s persistent soothing. Slowly, reluctantly, Sans found himself going limp.

“Hnngh,” he groaned, trying to fight the overwhelming feeling of peace, struggling to hold on to his fury at the violation. “Fucking…stop. Put it back.”

This time he was ignored entirely as both humans fussed over the state of his soul. Sans felt himself being prodded uncomfortably, some sort of electrode taped to either side of his soul leading to a nearby machine. The pressure made Sans hiss, his body jerking at the over-sensitive contact.

“Initial examination of the soul reveals the expected scars and fissures now associated with adult monsters after their release from the Underground,” the Doctor said, his voice pitched oddly as if he were speaking to an audience. Sans didn’t think the man was talking for his benefit. “Shape and integrity of the soul are healthy. Size is slightly larger than average for the mass of the subject, but in line with the data recorded from the other member of this subspecies. Subject may simply have an undersized physical form. Disparity between these two traits may have caused developmental difficulties including oversensitivity to environmental pressures and a difficulty adapting to the quantity of LOVE gained.”

Other member of the subspecies? Was he talking about Papyrus? Sans twitched, then tried to keep his expression blank and uninterested, or at least set in a fierce scowl. ‘Oversensitivity’ his ass.

“Base colour reads as hexidecimal code F0D9D9. Distinctive red hue is noted overlaying the natural base colour of monster souls.” The Doctor paused for a moment in his accounting to glance at Sans. “Is this the natural colour of your magic? Have you noticed it changing over time?”

Sans said nothing, jaw clenched, his face set in an ugly expression that he’d mastered to wordlessly convey, go fuck yourself. The Doctor shrugged philosophically to himself, turning away.

“The Subject has become noncompliant. Further questioning will be deferred until later sessions when treatment will likely increase the Subject’s cooperation.”

That causal assessment left Sans feeling cold, and he stole another glance at his captive soul. The Assistant, noticing the direction of his gaze, offered a smile that might have meant to be reassuring, but Sans was used to seeing that expression on the smug faces of enemies who thought they had one up on him.

“Did you want me to get started, Doctor?” the assistant asked, their fingers moving absently against Sans’s soul like it wasn’t a fucking huge deal that they were basically petting his core. Sans tried to keep his expression fixed but the delicate pressure combined with the gentle undertones of calm-concern-care made a hard shudder run up his spine. He sucked in a tight breath, eye-lights rolling as his spine arched involuntarily.

It felt…god, it felt kind of good. He didn’t want it to feel good.

“Stoooooop,” he whined, but even to his own ears he sounded pathetic. His voice had lost its edge, sounding meek and breathy and absolutely not like himself at all. What the fuck were they doing to him?

The Doctor’s lips quirked in a slight smile before he smoothed it back into professional indifference. “Subject is responding well to initial contact with their chosen handler. The compatibility assessment seems to have been successful. Beginning the next phase of treatment.”

He nodded to the Assistant, whose gaze on Sans sharpened unnervingly. Sans instinctively fought to hold their stare, just like he would have with any member of the Canine Unit. Dogs were simple creatures; whoever blinked first lost. Maybe humans were the same way, and Sans could glare this asshole into submission until he was forced to let go of Sans’s soul.

Except that very act of holding put Sans at a distinct disadvantage, especially when he felt the nature of the human’s intent changing. Their hands closed around him in a tight, suffocating cage, and through the sticky contact of their latex-covered palms he could feel the force of an emotion that was large and bright and absolutely terrifying. He whimpered, desperately trying to shore up what little defences his soul could maintain outside his body, valiantly blocking out that awful feeling they were trying to press into him.

“You don’t need to be afraid,” the Assistant murmured, the weight of his reassurance squeezing around Sans like a vise. “This is what love feels like. Just accept it.”

It didn’t match any of Sans’s experiences with LOVE. It was warm but fierce, like the burn of mustard in the back of his throat, or that infrequent spike of something whenever he saw Boss smiling at a well-crafted death trap. It was heavy and confusing and it wanted to sink its way deep into all his vulnerabilities, taking up residence like some sort of parasite in his brain, leaving him dazed and defenseless. He convulsed hard against the mattress, his screech of protest breaking on a sob of unfamiliar emotion, but he was already exhausted and the force of the human’s will – their kindness – was unrelenting.

(Fucking humans and their fucking determination and their fucking powerful souls and their fucking solid bodies and–)

Sans didn’t have the resolve to stand against them, and he crumbled with a crushed whimper of defeat, feeling the intrusion of foreign emotion in his soul, filling him up with a dizzying need for something. Unlike LOVE, which demanded isolation and distance, the love the human was forcing onto him seemed to demand some sort of reciprocation. His bones tingled unbearably, and he squirmed against the mattress and the restraints, trying to use the friction to placate the sudden awful yearning.

It took him a moment too long to realise that the red glow hazing his vision wasn’t coming from his eye, but from the rest of his bones which had begun emitting a soft, alluring light. Both humans were staring, but despite his utter mortification Sans couldn’t figure out how to suppress the uncomfortable swell of his magic. It was gathering with particular intensity around his pelvis, something unfamiliar taking shape between his legs and filling up his pelvic inlet.

The Doctor cleared his throat, eyeing the display panel at Sans’s beside which was chiming with new notifications. “Subject is responding to the treatment, and seems to have initiated some sort of sexual response. This seems to be a common reaction in monsters who have reached maturity but do not possess an existing mate, leading to further speculation on the role of soul touching in conjunction with monster reproduction…though monsters themselves have maintained that this is no longer a common practice among their kind.”

Hearing the human blandly discussing his reaction like it was no big deal they were violating his soul and manipulating his emotions and fucking turning him on inappropriately made Sans wish Frisk had been kind enough to kill him in the Judgment Hall. He wasn’t sure which was worse; the Doctor’s poor attempt at professional detachment, or the Assistant’s completely undisguised interest at what was happening between Sans’s legs.

The Doctor seemed equally intrigued, ignoring Sans’s obvious discomfort as he examined the coalescing magic intently. “The Subject seems to be trying to mimic compatible human organs to better achieve copulation. This may be due to the subject’s relatively minimal physical form compared to humans, or perhaps this is a common compromise for this subspecies to better adapt to other monster partners.” He paused for a moment, then looked at Sans. “I don’t suppose you would like to give us any insight on this behavior of your species in the name of science?”

Sans took a steadying breath, trying to make sure every word he spoke would be clear and understandable. “Let. Go. Of. My. Fucking. Soul. Or. I. Will. Kill. You. Both.”

The Doctor shrugged dismissively, apparently unperturbed, and Sans hated the thoughtful look that crossed his face. “Previous trials have found that other monster subjects have responded positively to physical and emotional encouragement during this time, although each experiment has been attempted on a case-by-case basis with deference to the Handler’s preferences…”

There was a meaningful pause, and the Assistant sat up straighter. “I’m happy to more fully engage with the subject, Doctor.”

“No!” Sans hissed, fighting the restraints as much as the soporific effect of the Assistant’s forceful calming of his soul allowed. “No! Fucking stop! Don’t touch me!”

The Doctor smiled benignly. “Very well. I will withdraw to allow the Handler to concentrate more fully on the subject’s responses. Full examination and analysis of the proceedings will be handled remotely.”

With little fanfare, the Doctor gathered his tools and materials and headed for the door. Meanwhile, the Assistant shifted his position from the chair at Sans’s bedside to the bed itself, his weight pressing an ominous dip in the mattress. Sans felt his eye-lights vanish, something close to terror taking over as the human gently cradled his soul in a single hand so that the other was free to caress Sans’s ribs.

The touch was electrifying, wonderful and wrong. It was heavy and wet and solid and unnatural and so utterly amazing that whatever was taking shape between his legs clenched in on itself in a way that sent a spike of pleasure rattling through his bones. The thrilling rush made his senses reel, and he felt sweet satisfaction radiating from the human’s hold on his soul. Of course; they could feel his pleasure. They knew exactly what effect they had on him.

“Everything will be all right,” the human said, reaching down to where a strange mound of red tinted psudo-flesh had formed over his pelvic bone. The solid mass of his magic was incredibly tender, and Sans bucked helplessly as they grazed his new organ with their fingers. They seemed to know exactly what they were doing as they stroked between his legs, their fingers running up the long slit that barely hid a cluster of much more sensitive nerves near its peak. “I’ll take good care of you. This will feel good, I promise.”

Sans could feel the bright emerald haze of the human’s magic seeping into him like a drug, and he knew that as much as he wanted to hate it, wanted to deny it, the human was telling the truth. They would make him enjoy it, and he had no way to refuse them.


End file.
